Spinning lathe

ABSTRACT

In a hot or cold spinning lathe for spinning a workpiece to a predetermined configuration there are provided means for rotatably mounting the workpiece on a headstock, a saddle mounted to be movable relative to the headstock in the axial direction thereof, a swivel head rotatably mounted on the saddle, a working tool mounted on the swivel head to be movable toward the center of the swivel, crank means for imparting a swivelling motion to the swivel head, means to vary the eccentricity of the crank means and a slide mounted on the saddle for supporting the crank means and the means for varying the eccentricity thereof, and means mounted on the saddle for sliding the slide on the saddle for adjusting the angle of swivelling of the swivel head.

lmited States Patent [1 1 Ashizawa et al.

[ SPINNING LATHE [75] Inventors: Yoshimi Ashizawa, Zama; lsao Kitagima, Yokohama, both of Japan [73] Assignee: Toshiba Kikai Kabushiki Kaisha,

Tokyo-to, Japan [22] Filed: Jan. 3, 1972 [21] Appl. No.: 214,870

[ July 31, 1973 Primary Examiner-Richard J. Herbst Attorney-E. F. Wenderoth, V. M. (rcedon cl al.

[57] ABSTRACT In a hot or cold spinning lathe for spinning a workpiece to a predetermined configuration there are provided means for rotatably mounting the workpiece on a headstock, a saddle mounted to be movable relative to the headstock in the axial direction thereof, a swivel head rotatably mounted on the saddle, a working tool mounted on the swivel head to be movable toward the center of the swivel, crank means for imparting a swivelling motion to the swivel head, means to vary the eccentricity of the crank means and a slide mounted on the saddle for supporting the crank means and the means for varying the eccentricity thereof, and means mounted on the saddle for sliding the slide on the saddle for adjusting the angle of swivelling of the swivel head.

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SPINNING LATHE BACKGROUND OF THE INVENTION This invention relates to a plastic working machine for metal and more particularly to a spinning lathe for closing or deforming an end of a metal pipe by a spinning operation.

Although the invention is applicable to cold spinning, for the sake of description, the following description will be in terms of a hot spinning lathe wherein the workpiece is heated to a plastic state before the spinning operation.

The spinning lathe of this type is more advantageous than other shaping or molding machines, such as a die forging machine and a swaging machine, in that it does not produce noise and does not require expensive metal dies.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved spinning lathe capable of shaping articles of various configurations with high dimensional accuracies.

Another object of this invention is to provide an automatic hot or cold spinning lathe capable of shaping articles of various configurations at high dimensional accuracies under control of a program control.

Still another object of this invention is to provide an improved spinning lathe of simple and rugged construction and yet which can finish a workpiece to the desired configuration accurately.

According to this invention, there is provided a spinning lathe comprising a headstock, means to rotatably support a workpiece on the headstock, a saddle, means to move the saddle relative to the headstock in the axial direction thereof, a swivel head rotatably mounted on the saddle, a working tool mounted on the swivel head to be movable toward the center of the swivel, crank means for imparting a swivelling motion to the swivel head, means to vary the eccentricity of the crank means, a slide for supporting the crank means and mounted on the saddle, and means to slide the slide on the saddle.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a plan view of a spinning lathe according to the invention;

FIG. 2 is a sectional view of the lathe shown in FIG. 1 taken along a line II-II;

FIG. 3 is a diagrammatic representation of the operating system for the working roll shown in FIG. 2;

FIG. 4 is a plan view showing the manner of shaping one end of a steel pipe into a closed hemispherical shape;

FIG. 5 shows a longitudinal section of the shaped end of the steel pipe;

FIG. 6 is a plan view showing the manner of shaping one end of a steel pipe into a form resembling the mouth of a bottle; and

FIG. 7 shows a longitudinal section of the pipe end shaped by the method shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2, a workpiece l, a steel pipe for example, is mounted on an automatic chuck 2 operated by pressurized oil or air after heating one end of the pipe in an independent heating furnace. A burner 3 may be used to maintain the workpiece at a proper working temperature. A working roll 4 made of heat resistant steel or alloy is rotatably mounted on one end of a ram 5 by means of a water cooled bearing, not shown. The ram 5 is constructed to act also as an oil pressure cylinder and is slidably received in a sleeve 6. A piston 7 is received in the bore of ram 5 and the outer end of the piston rod 7a is secured to a plate 9 which is fixedly secured to one end of sleeve 6. When pressurized oil is admitted into a chamber 8 to the right of piston 7, working roll 4 is urged against the side wall of the workpiece l. The details of the mechanism for urging working roll 4 against workpiece 1 will be described later.

A headstock 10 having the same construction as that of a standard lathe is provided. The head stock is hollow to receive the workpiece and is rotated at a speed commensurate with the diameter of the workpiece.

Beneath the workpiece 1 is mounted a swivel head 1 1 having generally the same construction as the turn table of a conventional vertical lathe. Swivel head 11 is supported on an upper saddle 14 on bearings 12 and 13. The sleeve 6 containing ram 5 is secured to the upper surface of swivel head 11 so that sleeve 6 rotates through a predetermined angle as the swivel head is swivelled to work the end of the workpiece.

Upper saddle 14 is slidably mounted on a lower saddle 15 so as to make possible adjustment of the axis of swivelling of swivel head I l in the lateral direction with respect to the axis of the headstock 10 which supports the workpiece 1. To adjust the axis of swivelling rotation of swivel head 11 in the axial direction of the headstock 10 or to feed the working roll 4 toward the workpiece during the spinning operation, the lower saddle 15 is connected to a driving device such as a piston cylinder assembly 29 and is slidable on a bed 16.

.A rotary joint 17 is contained in the upper and lower saddles 14 and 15 to supply pressurized oil to ram 5, lubricant to the bearing of roll 4 as well as sleeve 6 and cooling water to the shaft 4a of roll 4 and to the swivel head 11. Various pipes for the oil and water are neatly contained in a rotary joint 17 and are connected to the sources through flexible hoses 18.

Swivel head 11 is operated by a link 19 connected thereto by a pin 20. The opposite end of link 19 is connected to a crank disc 21 mounted on a shaft 22 which is driven by a driving mechanism such as an electric motor, not shown, through a worm 23 and a worm gear 24. For the purpose of adjusting the angle of swivelling of the swivel head 11, the length of the crank arm of crank disc 21 or the eccentricity e is made variable by adjusting the connection between the piston rod 30a of an oil pressure cylinder 30 and a block 31 which supports the crank pin 21a interconnecting lever 19 and crank disc 21, by means of an adjustable screw 30b. Accordingly, by actuating oil pressure cylinder 30 it is possible to adjust the eccentricity e while the crank disc 21 is rotating. The piston rod 25a of an oil pressure cylinder 25 is connected to a sliding base 26 which is used to house the worm gear so as to adjust the angle of swivelling (amplitude of the angular movement) of swivel head 11.

As is well known in the art, the working roll 4 is operated by a program control of any well known construction. FIG. 3 illustrates a typical example of such a control adapted to move the working roll 4 according to a prescribed program and comprising a synchrotransmitter 38 and a synchro-receiver 39 which functions to transform angular motion into voltage. More particularly, when the synchro-transmitter and receiver rotate in synchronism in the same phase, the output voltage of the synchro-receiver 39 is zero, but when they become out of synchronism, the synchro-receiver generates an output voltage having a magnitude proportional to the phase difference. This output is applied to the operating coil of an electromagnetic servovalve 37 to supply pressurized oil into the chamber 8 to the right of piston 7 (as viewed in FIG. 2) or to lefthand chamber 8 to advance or rectract working roll 4. As shown in FIG. 3, ram is provided with a rack 33 meshing with a pinion 32 mounted on the shaft of synchroreceiver 39 to feedback the movement of ram 5 to the rotor of synchro-receiver 39.

The opening of the electromagnetic servovalve 37 is varied in proportion to the input current. This valve may be constructed such that it acts as a four way valve to switch the flow of the the pressurized oil in response to the actual position of working roll 4 with respect to the prescribed program. In this manner, the feed of working roll 4 is controlled in accordance with the programmed rotation of synchro-transmitter 38.

The spinning lathe described above operates as follows. In the following description one end of a tubular workpiece 1, a steel tube for example, is to be closed so as to have a hemispherical section. After heating the end to a forging temperature, the workpiece l is mounted on chuck 2 and then headstock 10 is rotated. The lower saddle is set to position the axis of rotation of swivel head 11 at a position 0 shown in FIG. 4. Then the working roll 4 is set at the solid line position A shown in FIG. 4 with a radius of swivelling r Under these conditions, when the swivel head is rotated the working roll 4 is moved along an are a to a dotted line position B to deform the end of the workpiece. At this position, the working roll 4 is advanced and then rotated back to the original position A along an arc a By repeating these operations until finally the radius of swivelling is reduced to r,, the end of the workpiece is deformed or closed as shown in FIG. 5. The ratio of the thickness 2 at the closed end D to the wall thickness 1 of the pipe varies dependent upon the length 1 between the closed end and the axis of swivelling 0. For example, to achieve a relation t t, 2, the length 1 is selected to satisfy a relation 1 l.5r. Feedings of working roll 4 are made at points A and B by intermittently supplying pressurized oil to ram 5. The amount of feed at successive working stages is gradually decreased because the resistance to deformation of the material gradually increases with the increase in the thickness of the worked end from t, to t The program of the program control device is preselected to automatically perform the various steps described above.

Although not shown in the drawing, the movement of the ram 5 is fed back to the control device by means of a suitable position detector associated with ram 5 for operating the working roll closely in accordance with the prescribed program, thus providing a type of a profiling control with an electro-oil pressure servo-system.

When the working roll is reciprocated between positions A and B, no spinning work is performed until the work roll actually engages the workpiece. To improve the working efficiency it is desirable to limit the angle of swivelling of the working roll between positions B and C. This adjustment can be done by adjusting the eccentricity e of the crank disk 21 and the gap s between cylinder 25 and slide base 26 by means of pistoncylinder assembles 30 and 25, even during operation.

In the modified operation shown in FIGS. 6 and 7, the end of a steel pipe is shaped into a configuration resembling the mouth of a bottle. At first the work roll 4 is set to rotate about an axis 0 with a radius r, as in the case shown in FIG. 4. Then, the radius is changed from r, to r and the saddle 15 is operated to shift the center of swivelling from O to 0 Then, the work roll is rotated about new center 0 to work the workpiece. Then, the radius is changed to r and the center of swiv elling is shifted to 0 The work roll 4 is rotated about center 0 In this manner, the workpiece is worked successively by changing the position of the center of swivelling thereby gradually increasing the wall thickness. Intermittent feed of upper saddle 14 is imparted by the operation of the oil pressure piston cylinder assembly 29. As the wall thickness reaches a desired value the eccentricity e of crank disc 21 and the position of slide 26 are adjusted to vary the angle of swivelling with respect to the axis of the workpiece.

Then, while feeding the lower saddle l5 intermittently, work roll 4 is rotated about the centers of swivelling varying from O, to 0,. Again these operations are performed automatically by the program control.

In the spinning lathe of this invention, since the working roll is mounted on a saddle which is fed in the direction of the axis of the workpiece it is possible to select any desired radius of swivelling and the center of swivelling of the working roll with respect to the work piece and it is possible to successively work the workpiece to the finished configuration by successively varying the radius of swivelling to the most suitable value suitable for respective working steps. Further, it is possible to produce an article having a configuration as shown in FIGS. 6 and 7 by merely shifting the center of swivelling without the necessity of varying the angle and phase of swivelling, thereby increasing the field of application of the spinning lathe. Moreover, articles having complicated configurations can be readily formed by automatic operation.

As the swivel driving device comprises crank means the eccentricity and the center of rotation of which can be varied, it is possible to adjust the angle and the phase of swivelling to values suitable for the contour of the finished product with an extremely simple mechanism without the fear of fault, dimensional error and missoperation.

When the machine is constructed such that the shift of the swivel and the swivelling motion are carried out concurrently by an automatic control, articles having complicated configurations can be readily formed by simple operations and control. A plurality of swivel motions makes it possible to control the wall thickness dis tribution.

Although, the invention has been described in terms of hot spinning of a metal pipe it should be understood that the spinning lathe of this invention can also be used for cold spinning of metals and plastics and that instead of moving the saddle with respect to the fixed headstock, the headstock may be shifted with respect to a fixed saddle.

We claim:

1. In a spinning lathe the combination comprising a headstock, means for rotatably supporting a workpiece on said headstock, a saddle, means for moving said saddle relative to said headstock in the axial direction thereof, a swivel head rotatably mounted on said saddle, a working tool mounted on said swivel head and movable toward the center of said swivel head, crank means for imparting a swivelling motion to said swivel head, means coupled to said crank means to vary the eccentricity of said crank means, a slide mounted on said saddle and supporting said crank means and said means for varying the eccentricity thereof, and means mounted on said saddle for sliding said slide on said saddle for adjusting the angle of swivelling of said swivel head.

2. The combination according to claim 3 further comprising means for operating said working tool comprising a ram on one end of which said working tool is rotatably supported and having a closed cylindrical chamber at the opposite end, a sleeve mounted on said saddle slidably receiving said ram therewithin, a piston supported by said sleeve and slidably received in said closed cylindrical chamber and means for selectively admitting operating fluid into said closed chamber on the opposite sides of said piston.

3. The spinning lathe according to claim 4 further comprising a rotary joint between said saddle and the remainder of said lathe and by which said saddle is rotatably supported and including a bearing and pipings for supplying said operating fluid to said closed cylindrical chamber extending through said rotary joint.

4. The spinning lathe according to claim 3 wherein said crank means comprises a crank disc, a driven shaft on which said crank means is mounted, a block slidably mounted on said crank disc, a pin mounted on said block at a position eccentric with respect to the axis of said driven shaft, a pin eccentrically mounted on said swivel head, a link interconnecting said pins, and a piston cylinder assembly secured to said crank disc for moving said block thereby varying the eccentricity of said first mentioned pin, and wherein said means for sliding said slide comprises a piston cylinder assembly mounted on said saddle.

5. The spinning lathe according to claim 3 which further comprises a program control having memorized command signals corresponding to the movements of said saddle, said working tool and said slide and to the eccentricity of said crank means, means for successively supplying said command signals during the progress of the spinning operation, and driving means for said saddle, said working tool, crank means and said slide and coupled to said program control for operating and positioning these elements in response to said command signals. 

1. In a spinning lathe the combination comprising a headstock, means for rotatably supporting a workpiece on said headstock, a saddle, means for moving said saddle relative to said headstock in the axial direction thereof, a swivel head rotatably mounted on said saddle, a working tool mounted on said swivel head and movable toward the center of said swivel head, crank means for imparting a swivelling motion to said swivel head, means coupled to said crank means to vary the eccentricity of said crank means, a slide mounted on said saddle and supporting said crank means and said means for varying the eccentricity thereof, and means mounted on said saddle for sliding said slide on said saddle for adjusting the angle of swivelling of said swivel head.
 2. The combination according to claim 3 further comprising means for operating said working tool comprising a ram on one end of which said working tool is rotatably supported and having a closed cylindrical chamber at the opposite end, a sleeve mounted on said saddle slidably receiving said ram therewithin, a piston supported by said sleeve and slidably receiVed in said closed cylindrical chamber and means for selectively admitting operating fluid into said closed chamber on the opposite sides of said piston.
 3. The spinning lathe according to claim 4 further comprising a rotary joint between said saddle and the remainder of said lathe and by which said saddle is rotatably supported and including a bearing and pipings for supplying said operating fluid to said closed cylindrical chamber extending through said rotary joint.
 4. The spinning lathe according to claim 3 wherein said crank means comprises a crank disc, a driven shaft on which said crank means is mounted, a block slidably mounted on said crank disc, a pin mounted on said block at a position eccentric with respect to the axis of said driven shaft, a pin eccentrically mounted on said swivel head, a link interconnecting said pins, and a piston cylinder assembly secured to said crank disc for moving said block thereby varying the eccentricity of said first mentioned pin, and wherein said means for sliding said slide comprises a piston cylinder assembly mounted on said saddle.
 5. The spinning lathe according to claim 3 which further comprises a program control having memorized command signals corresponding to the movements of said saddle, said working tool and said slide and to the eccentricity of said crank means, means for successively supplying said command signals during the progress of the spinning operation, and driving means for said saddle, said working tool, crank means and said slide and coupled to said program control for operating and positioning these elements in response to said command signals. 